1. Field of the Invention
This invention relates to an automatic stop motion device in a motor drive camera which automatically cuts off the supply of current to a motor to stop film winding when photographic film is wound by an effective number of frames or when the film is caught to prevent film winding.
2. Description of the Prior Art
Heretofore, an automatic stop motion device for a motor is known which mechanically detects the slip of the motor caused by a friction mechanism when film winding is impossible, thereby cutting off the supply of current to the motor.
However, such conventional device which mechanically detects the slip of the motor has suffered from the following disadvantages:
(1) When the source voltage drops, the drive of the motor is reduced and the motor is stopped from running in spite of a current flowing thereto. This results in the heating of the motor or injuries imparted to the film; and
(2) The mechanism for detecting the slip of the motor is complicated and requires a large space.